1. Field of the Invention
The present invention relates to a light-emitting diode display device (hereinafter, simply referred to as an "LED display device") having a display area where a plurality of light-emitting blocks, each corresponding to one dot, are arranged in a matrix.
2. Description of the Related Art
In order to obtain an LED display device capable of displaying a plurality of colors so as to realize, for example, a full-color display or a multi-color display, each of light-emitting blocks, which corresponds to one dot of the LED display device, needs to emit at least light of three basic colors, namely, red (R), green (G) and blue (B) light.
In a conventional LED display device, the light-emitting blocks each include three light-emitting diodes (hereinafter, simply referred to as "LEDs") corresponding to R signals, G signals and B signals, respectively. Each of such LEDs is associated with an input processor for receiving one of the RGB signals, a color arithmetic circuit for adjusting colors and an ON/OFF controller for controlling the ON/OFF state of a display circuit. In other words, the conventional LED display device includes LEDs each having a three-unit structure corresponding to the RGB signals.
However, conventional LEDs have insufficient light-emitting characteristics for displaying a color close to a pure (monochromatic) green color. Therefore, each light-emitting block is formed to consist of a red LED, a blue LED and a yellow-green LED, where the yellow-green LED is driven by the input processor, the color arithmetic circuit and the ON/OFF controller such as to emit light having a color closer to a pure green color.
Although red and blue colors obtained by such a conventional LED display device can stand comparison with those obtained in a television, a CRT or the like, color reproducibility of the conventional LED is poor in a green color region.
In theory, it is possible to produce a green LED capable of emitting pure green light. However, this would involve a large amount of cost and trouble.